UV-Electron Beam Curing for Resin Without Initiators
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Solution Overview
Problem
Photocurable resins and electron beam-curable resins without a photopolymerization initiator face challenges such as monomer volatilization and smoke formation during electron beam irradiation, which complicates the curing process.
Innovation Solution
A curing method that involves irradiating ultraviolet rays to polymerize the surface layer of the resin, followed by electron beam irradiation to cure the deeper layers, under a low-oxygen atmosphere to prevent oxygen inhibition and reduce smoke formation, allowing for complete curing without the need for a photopolymerization initiator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electron beam irradiation is used to cure curable resin without photopolymerization initiator, then curing can be achieved without residual initiators, but monomer volatilization and smoke formation occur
Solution Approach 1:
The patent applies preliminary UV irradiation to form a cured film on the surface layer of the resin before electron beam irradiation. This preliminary action creates a protective barrier that prevents monomer volatilization and smoke formation during subsequent electron beam curing, while still achieving complete curing throughout the resin layer
Solution Approach 2:
The patent divides the curing process into two distinct stages: first UV irradiation for surface layer curing, then electron beam irradiation for deep layer curing. This segmentation allows each irradiation method to operate in its optimal range, with UV handling the surface and electron beam penetrating to deeper layers, thereby preventing harmful volatilization while achieving complete curing
2Loss of energy
If UV light source with low illuminance is used, then energy consumption is reduced, but curing efficiency decreases and photopolymerization initiator content must be increased
Solution Approach 1:
The patent changes the curing approach by eliminating the need for photopolymerization initiators entirely and using a two-stage irradiation process. This parameter change allows the use of lower illuminance UV LEDs while maintaining high curing efficiency through the complementary action of UV surface curing and electron beam deep curing
Solution Approach 2:
The patent introduces electron beam irradiation as an intermediary process that complements UV irradiation. The electron beam serves as a mediator that can penetrate deeper into the resin and cure layers that UV light alone cannot reach efficiently, thereby maintaining high productivity without requiring high illuminance UV sources or increased initiator content
3Ease of operation
If oxygen is present during electron beam irradiation, then the process is simpler, but oxygen inhibition occurs and curing is incomplete
Solution Approach 1:
The patent applies preliminary UV irradiation to form a cured film on the surface before electron beam irradiation. This cured surface layer acts as a barrier that reduces oxygen access to the resin during electron beam curing, thereby preventing oxygen inhibition while maintaining process simplicity
Solution Approach 2:
The patent applies preliminary UV irradiation to pre-cure the surface layer, which creates a protective barrier against oxygen inhibition during the subsequent electron beam irradiation. This preliminary anti-action prevents the harmful effect of oxygen from interfering with the curing process
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method ensures efficient curing of the resin from the surface layer to the deep parts, preventing oxygen inhibition and reducing smoke occurrence, thereby achieving high-quality curing without residual monomers or initiators, suitable for various printing techniques like inkjet, offset, flexographic, and gravure.
Implementation Method 1
irradiating ultraviolet rays to polymerize the surface layer of the resin
Implementation Method 2
electron beam irradiation to cure the deeper layers
Data Source
Figure 1
Figure 2A~2C
Figure 3
AI summary
To cure, with light irradiation, photocurable resin or electron beam-curable resin not containing a photopolymerization initiator. Under an atmosphere equal to or lower than predetermined oxygen concentration for not causing oxygen inhibition to polymerization of photocurable resin or electron beam-curable resin, an ultraviolet ray in wavelength region corresponding to a light absorption characteristic of the photocurable resin or the electron beam-curable resin is irradiated on the photocurable resin or the electron beam-curable resin to polymerize the photocurable resin or the electron beam-curable resin. After an ultraviolet ray is irradiated on the photocurable resin or the electron beam-curable resin to polymerize at least a surface layer, an electron beam is irradiated on the photocurable resin or the electron beam-curable resin to polymerize a deep part, and the entire photocurable resin or the entire electron beam-curable resin is cured.